Cold weather, engine runing rough

[Le_Combattant]

Hey fox, hops you doing well,

Winter is coming slowly and my car seems to have a strange feeling when cold.

PXL_20230228_145825557.jpg (403.05 KiB) Viewed 1559 times

1.2 TSI, 66kw engine with 141000km.

When cold, I let it perform it's cold start + 1/2 minutes of running at idle.
On flat surface, everything is fine but one on false flats or hills, with the same accelerator pedals positions, engine is giving some light jerks between 1500-2000 rpm.
But since I drive it every day, I know how the engine feels.

When cold, it start fine, warm too.
The jarking are only when the car is cold.

When the engine is warm, she's running fine.

Spark plug
Fuel filter
Air Filter
Oil

All those items were changed 1000 km. The weather at this time was warmer and no issue at all.

With my OBDEleven I checked:

-Turbo pressure (requested and current value)
-Fuel pressure (requested and current value)

No fault, no codes.

Some people said to me that on this engine, fuel injector are weak. First time I heard that.

Could be also coil igniter or camshaft sensor, all are original and 9 years old/141000 km.

What do you think about that ?

[Le_Combattant]

No idea ?

[phc606]

I have a similar issue and been told it can be the Cam belt or chain as they can stretch. Ours sound quite rattly on first start, and like yours can rev lumpy for 10/20 mins or more, seems to be worse in cold and damp.

We've had the plugs and fuel filters changed. oddly seems better at the mo than it's been for a while but I suspect next step is the cam belt etc.

would really like to know what it is for sure.

[ciclo]

It could also be the quality of the fuel... with the price increases...blah blah blah

I think it happened to me once when my 1.2 TSI CBZC was very new, some slight 'jerks' during cold start, in first gear moving without accelerating.

[Le_Combattant]

It could also be the quality of the fuel... with the price increases...blah blah blah

I think it happened to me once when my 1.2 TSI CBZC was very new, some slight 'jerks' during cold start, in first gear moving without accelerating.

Total Excellium SP98: alaways so I don't know.
Jerking at cold start are quite common on this engine. The fuel mixture is high to warme the Particul Filture faster.

I suspect the coil pack. They are original from factory so 9 years and 141000 km. I have the Wiring Diagramm but no refence values If I have to test them.

[iichel]

a faulty coil makes sense, but it doesn't without an error code. do you have any error codes for a misfire?

[Le_Combattant]

a faulty coil makes sense, but it doesn't without an error code. do you have any error codes for a misfire?

I run OBDElven on my car with live data to check missfire on all cylinder.
During the firt start I have some miss fire detected by the engine and the OBDElven.

At low speed, engine cold, some missfire are also detected. But not enough to generate code or light on dashboard.
But when the engine is warm, is very rare. Somes, but very rare.

Some people said it's quite common on TSI engine at low speed, low engine speed. Air flow is not "fast" enough to properly mix with fuel injected in combustion chamber.
Higher boost and higher RPM are, better is the combustion and lower are miss fire.

[iichel]

alright, so we have something to start on... do you have misfires on one specific cylinder or multiple?

[Le_Combattant]

alright, so we have something to start on... do you have misfires on one specific cylinder or multiple?

All cylinder are concerned by missfire.
At least, I have between 24500 and up to 36000 missfire (cylinder 1) recorded by ECU and those values are readable on OBDevelen.

I think those values I recorded since the car left the factory in September 2014.
But overall, car run great, start on quarter turn and fuel consumption is goof (5-6L/100km) and no oil is burning.

[iichel]

okay so i guess we can rule out any specific cilinder that is misfiring. is your car dsg or manual? 1.2 TSI MQB has a timing belt, so we can rule out a bad timing chain.

[Le_Combattant]

okay so i guess we can rule out any specific cilinder that is misfiring. is your car dsg or manual? 1.2 TSI MQB has a timing belt, so we can rule out a bad timing chain.

It's a manual one, so we can put out the gearbox haha

[Le_Combattant]

I went to my local dealer to buy new ignition coil.

100 euros per coil.
What the hell

Cost me less if I go to ARP Coil or buy VW OEM in Lituania.

[ciclo]

At Autodoc you can search by part number/reference and you will find a wide variety of brands, including the coils used by VW. Prices are reasonable compared to other places. Shipping will be free if the cost exceeds €120.

I imagine you already knew this, but I leave it here as info for other users.

[Le_Combattant]

At Autodoc you can search by part number/reference and you will find a wide variety of brands, including the coils used by VW. Prices are reasonable compared to other places. Shipping will be free if the cost exceeds €120.

I imagine you already knew this, but I leave it here as info for other users.

Yup, It's what I did but I was not sure depending of the brand and quality.
I paid 294 euros for brand new 04E905110P (25 euros of shipping, hurt me) but I will be sure about quality.

Eldor, official manufacturer for my car, was not available, just Beru. And all other one, Bosh, NGK etc...

[ciclo]

This is what I usually do, buy original VW spare parts, although for testing and other purposes I also buy parts from the brands that VW uses on Autodoc, Amazon, Ebay, etc...

For one reason or another, at the moment I am 99.99% satisfied with the purchases I made at Autodoc, in addition to the good customer service.
I think it's a good place for delicate pockets.